Evaluation of the National Salmon Management Plan (38257/106768 & 111341)

A National Management Plan (MP) for the (endangered) remaining Danish populations of Atlantic salmon was issued in 2004. The plan includes stocking, fishing regulations and massive river habitat/connectivity improvements, but no monitoring plan to evaluate the effect and assess the current status of the populations/runs in the 4 rivers covered by the MP.

This project closes the information gap and provide basic information on the salmon runs to enable proper management decisions. Every year monitoring is carried out in one or two of the 4 rivers covered by the MP, so each river will be surveyed every 2 or 3 years. The aim is to collect enough data on the population developments to set biologically feasible Conservation Limits (CL) in accordance with NASCO requirement.

Intensive electrofishing from boat is carried out just after the season closure (October) in the main river and in some tributaries, where all salmon are measured (TL, sex) and PIT tagged. In November during the regular electrofishing for broodstock, the proportion of tagged individuals gives a measure of the sampling efficiency and provides basis for an estimation of population size. The composition in terms of size, sex and origin (stocked fish are fin-clipped) can also be estimated.

In each of the 4 rivers the most important/preferred spawning areas were identified using radiotelemetry. Both present and potential spawning and rearing habitat have been assessed by standard monitoring and electro-fishing for juveniles in order to judge the present production in relation to the potential production. Naturally spawned fry were genetically analyzed to assess the number of families present on each spawning area. The presence of several families indicate a well-functioning and well-visited spawning area, whereas few or single families indicate lack of spawners.

Due to good status of the population in Storå, all stocking was terminated in 2018, thus making Storå the first “all wild fish” river in Denmark. The plan is to phase out stocking whenever a population show repeatedly good runs of wild spawners. During the last 5 years, also other salmon rivers where stocking takes place and quotas are in force, have been surveyed for size of spawning run, this has been done in: Kongeå, Sneum Å (twice), Vidå and Brede Å.
Annual reports from the project are used for adaptive management measures like quota setting, fishing season and stocking.
Partners
National Institute for Aquatic Resources, DTU Aqua
Danish Centre for Wild Salmon, Denmark

Funding

The project is funded by the Danish Rod and Net Fishing Licence Funds.


Research area: Freshwater Fisheries and Ecology

Research area: Population Genetics